Magainins and the disruption of membrane-linked free-energy transduction

Magainins, a family of positively charged peptides, are partly if not wholly responsible for antimicrobial activity in skin extracts of Xenopus laevis. We report here that members of the magainin family--i.e., the 21-amino acid peptide PGLa and the 23-amino acid peptide magainin 2 amide (PGSa)--dissipate the electric potential across various energy-transducing membranes and thus uncouple respiration from other free-energy-requiring processes. We propose that this is a likely mechanism for the antimicrobial effects of these compounds.